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Transporting massive quantities of carbon dioxide through a pipeline in its supercritical state is extremely convenient. Because of the unique properties of supercritical carbon dioxide, however, leakage occurring in such conditions can be extremely intricate, resulting in the dispersion area following leakage being influenced by numerous factors. In this study, this problem is addressed in the frame of the so-called Unified Dispersion Model (UDM), and various influential parameters are considered, namely, leakage pressure, leakage temperature, leakage aperture, leakage angle, atmospheric stability, wind speed, and surface roughness. The results show that the supercritical carbon dioxide dispersion is primarily influenced by high air temperatures, low wind speeds, reduced surface roughness, and release temperatures slightly below the critical temperature. Additionally, leak apertures also contribute to the dispersion. The dispersion is maximized under atmospheric stable D conditions, and when the leakage angle is 0°, the farthest downwind distance is 10 times greater than that at a leakage angle of 90° under the same conditions. [ABSTRACT FROM AUTHOR]

The dispersion of titanium dioxide (TiO2) determines the performance of TiO2-based formulations in cosmetic and coating applications. In particular, the chemical and structural characteristics of the surfactants used to prepare TiO2 dispersions are significant. However, the influence of surfactants on TiO2 dispersion quality has not been systematically investigated. In this study, we observed the effects of the ionic character of commercial surfactants on the dispersion stability and UV-blocking efficacy of TiO2. Among the experimental surfactant groups, anionic sodium dodecyl sulfate was efficient in stabilizing TiO2 as a water-in-oil formulation and enhancing its UV-blocking efficacy. Furthermore, an anionic fatty acid as a surfactant with a longer alkyl chain length was sufficient to stabilize the TiO2 formulation, which also displayed the highest UV-blocking efficacy, comparable to the values of commercial TiO2-based cosmetic products. [ABSTRACT FROM AUTHOR]

Considering scattering behaviors of strength and fatigue life characteristics of actual materials, a method for evaluating the early fatigue failure of crankshafts has been proposed. The micro-mechanism of the scatter of strength and life characteristics is the nonuniform distribution of microstructures (including micro-defects) inside the material, which can be uniformly characterized by the probability distribution of initial damage. For the same grade of alloy, the median values of strength and fatigue life can be basically the same, but the dispersion can be significantly different, which must be determined by sufficient sampling tests. For a diesel engine crankshaft forging made of the 34CrNi3MoA alloy, the dispersion of fatigue limit was estimated based on the scatter of impact sampling test data, while the mean value of probability distribution of fatigue limit was determined by structural fatigue tests. The safety factor recommended in the conventional design manual only implicitly assumes material dispersion. Considering the actual dispersion of the tested material, the quantitative relationship between safety factor and reliability has been established. Early fatigue failure of the crankshaft can easily occur when the actual dispersion of material fails to meet the specified reliability requirement.

The paper considers a planar chiral metamaterial of the optical spectrum. The material parameters of metamaterial depend on the frequency and one spatial coordinate. The mathematical model of metastructure is based on the well-known dispersion models of the permittivity, permeability and chirality parameter. A novelty in the mathematical model of a metamaterial is the consideration of the heterogeneity of all material parameters. In this paper we consider a problem of the incidence of a plane linearly polarized optical wave on a planar layer of a chiral metamaterial. We develop a method for calculating reflection coefficients of an optical wave from the considered inhomogeneous chiral structure, which is based on using a differential sweep method. When constructing a mathematical model, the cross-polarization of the optical wave field was taken into account, which consists in the appearance of orthogonal components during the interaction of the field with a chiral metamaterial. The solution of the problem was reduced to a matrix differential equation for the unknown reflection coefficients of the main and cross-polarized components of the optical field. Chiral metamaterials with linear and parabolic inhomogeneity profiles were considered in the work. Based on the results of numerical calculation of reflection coefficients of the main and cross-polarized components, it is proved that the inhomogeneity of the material parameters leads to a significant decrease in the level of cross-polarized component of reflection. It is shown that the use of inhomogeneous chiral layers also makes it possible to lower the level of reflection of the optical field main component. It is also proved that a layer of a planar inhomogeneous chiral metamaterial in the optical spectrum reflects waves of s- and p- polarizations differently.

Background. Currently, in geocryology, to predict seasonal changes in the state of frozen rocks and soils, Fourier formulas obtained earlier are widely used, modeling temperature fluctuations in the surface layer of the earth’s crust caused by annual fluctuations in its surface temperature. A significant drawback of this approach to modeling is manifested in the fact that in reality the state of the medium is characterized not only by the temperature field, but also by the moisture content field, which Fourier theory does not contain. Aim. It is required to generalize the Fourier problem known in mathematical physics on fluctuations of the temperature field in half-space by introducing into consideration, along with the temperature field, the moisture content field and taking into account the phenomena of evaporation and condensation associated with this field. Methods. Within the framework of A.V. Lykov’s theory, a spatially one-dimensional mathematical model of the processes of heat and moisture propagation in a homogeneous half-space, the boundary of which is in a state of heat and mass exchange with an airless medium, has been developed. By the method of complex amplitudes, formulas are obtained for time-asymptotic fluctuations in temperature and moisture content in a material filling a half-space, provided that the air temperature changes according to a harmonic law, and water vapor, both near the surface of the material and outside the boundary layer, is in a state close to saturation. Results. According to the results obtained, the temperature field is represented by a superposition of two damped harmonic waves, which have the same frequency, but different attenuation coefficients and phase velocities. The moisture retention field has the same structure. For a material with clay characteristics and with specific values of all the process-defining quantities for each of the waves, the depth of penetration and the delay time of vibrations at a given depth relative to fluctuations in air temperature are calculated, and the results obtained are compared with experimental data. Conclusion. The proposed solution and the following conclusions from it are the development of Fourier studies known in the literature on fluctuations in the temperature field in the surface layer of the Earth’s crust and are valid only in a situation when the material does not contain moisture, and according to the harmonic law, the temperature of the surface of the material does not change. The results of the work can be used in geocryology as a theoretical tool for modeling seasonal fluctuations in the thermal state of frozen rocks and soils.

Twelve soil samples of different textures and carbonate minerals were selected from the great soil group (Calciortheds) in northern Iraq. In order to describe the effect of the concept of mono cations ratios (potassium and sodium) responsible for the stability of soil aggregates CROSS as an alternative to the concept of sodium adsorption ratio, on the water conductivity and the average weighted diameter of soil aggregates, an electrolyte solution consisting of mono cations (potassium and sodium) and divalent cations (calcium and magnesium) with potassium ionic dominance over the rest of the other ionic species was allowed at a concentration of (4.26) mmol.L1/2 to undisturbed soil columns with a diameter of 4cm and a length of 6 cm using the miscible displacement technique under the influence of a constant flow solution pressure of 4cm. For ten successive pore volumes for approximately 16 weeks. The flow of electrolyte solution through the columns led to increasing additions of mono cations (K+) that negatively affected the deterioration of different soil groups by sliding their colloids from the original aggregate, causing dispersion of clay colloids dominated by montmorillonite mineral with high ability to swell and disperse clay particles and sliding organic materials, which led to a decrease in the weighted diameter index from 6.18 to 5.43 mm, which led to the deterioration of the soil and a decrease in its water conductivity for all soils from 3.39 to 1.61 cm.h-1. we suggest that the effect of potassium should be taken into account in evaluating soil structure.

El objetivo fundamental de este trabajo consiste en presentar una visión general de la distribución del léxico en los diferentes países hispánicos. Los datos proceden del Diccionario de Frecuencias Léxicas, incorporado a la versión 1.1 del CORPES, construido sobre 180 millones de formas procedentes de los textos de prensa de este corpus. Los resultados obtenidos, que utilizan también en los índices de dispersión, muestran un alto grado de congruencia, relacionada con la frecuencia de uso, compatible con la esperable diferencia entre las variedades, fundamentada en la frecuencia de inventario.

Weakly bound complexes of inert gas atoms with aromatic rings have received the attention because these are important for understanding the several solution- and condensed-phase properties. Extrapolated complete basis set (CBS) limit interaction energies for van der Waal complexes of benzene with He, Ne and Ar were calculated by using MP2 level and B2PLYPD3 and M06-2X functionals, employing aug-cc-pVTZ basis set. It was observed that as the size of inert gas increases, the interaction energy becomes more negative suggesting more stabilizing interaction. In sandwich complexes, the magnitude of CBS interaction energies was found to be double when compared to benzene complexes. The calculated vibrational stretching frequencies of cationic benzene complexes show red-shift, whereas almost same frequencies are found in sandwich complexes, with respect to benzene–X (X = He, Ne and Ar) complexes. However, in deuterated benzene–X complexes, the C–D stretching frequencies show a decrease in frequency value compared to benzene–X complexes and this may due to the presence of deuterated atom. Apart from that, the complexes, (benzene)++–X dication and X–(benzene)+–X sandwich cation were also studied using MP2/aug-cc-PVTZ level. It is observed that the charge is increased when moving from (benzene)+–X to (benzene)++–X complexes, the strength of interaction is increasing. Further, the nature of interaction present in benzene–X complexes was investigated by energy decomposition analysis using SAPT analysis. The SAPT analysis revealed that the contribution from dispersion terms is increasing when moving from He to Ar complexes. [ABSTRACT FROM AUTHOR]

The advancement of carbon nanotube (CNT) polymer composites has significantly revolutionized material science by offering exceptional mechanical, electrical, and thermal properties. However, the practical application of these composites is often hindered by the poor dispersion and compatibility of CNTs within polymer matrices. This paper explores advanced functionalization techniques to address these challenges, aiming to achieve superior dispersion and compatibility. Through a comprehensive review of chemical, physical, and hybrid functionalization methods, this study evaluates their effectiveness in enhancing CNT-polymer composite properties. Additionally, key characterization techniques, including spectroscopic and microscopy methods, are utilized to assess the quality of dispersion, interfacial bonding, and the presence of functional groups. Detailed case studies showcase the successful application of these advanced functionalization techniques, with significant improvements in mechanical properties such as tensile strength, modulus, and fracture toughness, resulting in composites with enhanced performance. This research advances the understanding of functionalization strategies and provides a robust framework for future studies and industrial applications, paving the way for the commercialization of high-performance CNT-polymer composites. HIGHLIGHTS: Tailored functionalization optimizes electrical and mechanical performance. Hybrid functionalization enhances CNT dispersion in polymer matrices. Covalent and noncovalent methods combine for superior composite properties. Improved interfacial bonding boosts tensile strength and thermal stability. Enhanced CNTpolymer compatibility leads to advanced industrial applications. [ABSTRACT FROM AUTHOR]

This study focuses on the effectiveness of a new substance in stabilizing paper information carriers - hydrotalcite applied to the paper in a partially polar environment. The effect of modification on the stabilization of paper during accelerated aging was investigated by measuring chemical (surface pH, rate of glycosidic bond cleavage), mechanical (coefficient of the relative increase of the lifetime for folding endurance), optical (colorimetry - CIE L*a*b*), and spectral (FTIR) properties. Three types of hydrotalcites differing in composition, particle size, and preparation conditions, were tested and compared. After the modification, all the properties of acidic test papers improved. The most promising type of hydrotalcite was prepared under the nucleation action of citric acid. The atomic ratio of Mg2+ to Al3+ of this hydrotalcite was equal to 5. Modification by this hydrotalcite led to an increase in surface pH by 1.3 to 2.7 units.

Fiber optic research continues to develop due to the need for fast information technology. The input signal in an optical fiber is in the form of a soliton wave that propagates in the fiber with a balanced index of refraction, dispersion, and diffraction. Fiber optics may lose some of the signal over time if they solely use a nonlinear refractive index. This study aims to examine into the dynamics and decoherence of multi-peak solitons caused by electromagnetic signal attenuation and potential trap in the propagation via optical fibers. The methods used start with the stationary solution of the nonlinear Schrödinger Cubic Quintic equation, the Newton-Raphson method, and the fourth-order Runge-Kutta. In stationary solutions, the p (state energy) and ρ (Lèvy index) values affect the number, pulse width, and height of soliton peaks. Increased p and ρ values lead to increased instability, causing the data transmitted into the optical fiber to collapse and become unreadable by the receiver. In the excited state (p > 0), the decoherence phenomenon occurs and causes wave instability and destruction. In term of energy intensity, a stable form of transmission in the ground state has a pattern of continuously weakening, decreasing, and smoothing, while in the excited state there is a spike in the intensity of the electromagnetic wave. Based on this study, multi-peak solitons can only be applied for propagation distances, which tend to be short due to their dynamics and decoherence.

Introduction/purpose: Fractured formations recently gained significant interest as a landscape for securing both energy and groundwater demands, However, the dual role of fracture in transporting fluids and contaminants underscores the need for further investigations to mitigate the impact on human health. This study aims to numerically investigate the combined effect of particle density and flow velocity on their transport and deposition in different fracture orientations. Methods: A 2D particle tracing simulation was implemented accounting for drag and gravity forces on a smooth fracture. The derived particle numbers under the studied scenario e.g., fracture orientation, particle density, and flow velocity, were fitted to a 1D advection-dispersion equation with a deposition term. Results: The model elucidated that both particle densities yielded an increase in the normalized concentration in non-horizontal scenarios as the fracture orientation angle increased. The overall increment led to an observed decrease in the deposition coefficients and was associated with an increase in the dispersion coefficients. Hence the effect was more pronounced for denser particles where gravitational settling dominated, particularly in horizontal fractures. Less dense particles (1.05 g/cm³) were more strongly influenced by hydrodynamic forces, exhibiting lower overall deposition and dispersion across all fracture orientations. Additionally, increased flow velocity enhanced mechanical mixing and amplified dispersion and deposition coefficients. Conclusion: The findings demonstrated a clear dependency on the combined effect of fracture orientation, particle density, and flow velocity. These valuable insights into particle transport mechanisms in fractured media have applications in subsurface flow, contaminant migration, and reservoir engineering.

Abstract Particle tracking (PT) is a popular technique in microscopy, microfluidics and colloidal transport studies, where image analysis is used to reconstruct trajectories from bright spots in a video. The performance of many PT algorithms has been rigorously tested for directed and Brownian motion in open media. However, PT is frequently used to track particles in porous media where complex geometries and viscous flows generate particles with high velocity variability over time. Here, we present an evaluation of four PT algorithms for a simulated dispersion of particles in porous media across a range of particle speeds and densities. Of special note, we introduce a new velocity-based PT linking algorithm (V-TrackMat) that achieves high accuracy relative to the other PT algorithms. Our findings underscore that traditional statistics, which revolve around detection and linking proficiency, fall short in providing a holistic comparison of PT codes because they tend to underpenalize aggressive linking techniques. We further elucidate that all codes analyzed show a decrease in performance due to high speeds, particle densities, and trajectory noise. However, linking algorithms designed to harness velocity data show superior performance, especially in the case of high-speed advective motion. Lastly, we emphasize how PT error can influence transport analysis.

Background. The using of mirror asymmetric chemical compounds for doping quartz makes it possible to metamaterial creation that has the chirality property. In such a compositional structure, unusual effects may arise when interacting with an optical wave. Aim. We calculate the transmission and reflection of a linearly polarized optical wave through a multilayer structure consisting of two doped quartz glasses separated by two air gaps. Methods. Based on a homogeneous mathematical model of a chiral metamaterial, taking into account the dispersion of the dielectric constant and the chirality parameter based on the matrix method, a system of linear algebraic equations is obtained for the complex reflection and transmission coefficients of an electromagnetic wave of linear polarization. Results. An analysis of the frequency and angular characteristics of the modules of the reflection and transmission coefficients was carried out at various values of the quartz doping level. It is theoretically predicted that at some wavelengths, most of the incident optical energy can be concentrated in the air gaps of the multilayer structure. Conclusion. The data obtained as a result of calculations can be used in the development of planar structures for frequency-selective concentration of energy in the visible and infrared spectrum based on quartz glasses doped with chiral chemical compounds.

Purposes For improving the mechanical properties of GO incorporated cement paste, two types of nano-silica (crystalline and amorphous) and coal-bearing metakaolin (CMK) were used seprately to improve GO dispersion in cement paste. Methods UV-vis spectrophotometry was used to investigate the effects of ultrasound time and different dosages of amorphous nano-silica (ANS) and crystalline nano-silica (CNS) on the dispersion of GO in saturated calcium hydroxide solution. The effects of different particle materials on GO dispersion were characterized by using compressive strength results. The dehydration and decomposition processes of various phases of hydration products were observed by thermogravimetric (TG) analysis, and the effect of adding different particle materials and GO on the pore structure of cement paste was analyzed by mercury intrusion porosimetry (MIP). Findings According to UV-vis spectroscopic study, when the contents of ANS and CNS were 2% and 1.5% by weight of cement, respectively, GO dispersion in saturated Ca(OH)2 solution is improved greatly. Compared with two nano-silicas, CMK is more effective to improve the compressive strength of GO incorporated cement paste. At the age of 28 d, the flexural strength and compressive strength of the cement paste incorporated with 4% CMK and 0.03% GO are 26.93% and 30.41%, respectively, higher than those of a plain cement paste sample. The results of TG and MIP tests showed that the pozzolanic reaction of CMK can effectively refine the pore structure of cement paste, improve GO dispersion, and enhance the bonding between hydration products and GO, which is the main reason why CMK can effectively improve the mechanical properties of GO incorporated cement paste.

Physical doping is a general and effective strategy to fabricate host‐guest room temperature phosphorescence (RTP) polymer materials. However, some aggregates of phosphors will appear due to their limited solubility and phase separation in polymer matrix, resulting in unstable and/or poor RTP property. In this work, a new strategy, the utilization of cyclodextrins with fit cavity size, is proposed to improve the dispersion of phosphors and enhance RTP performance both in covalent and ionic bond system. The resultant high Förster resonance energy transfer (FRET) efficiency (ΦFRET) and outstanding RTP performance confirmed that the added cyclodextrins can effectively disperse fluorescence dye (guest) in covalently modified sodium alginate (SA‐R) matrix. Thanks to the introduced “ FRET ruler”, the distance between energy donor and acceptor can be measured, accompanying with the afterglow color of SA‐R films changing from green to red. For SA‐NpC@RhB, the introduction of β‐CD can enhance the ΦFRET up to 57.4%, with corresponding photoluminescence quantum yield (ΦPL) as high as 21.15%. The ΦFRET for SA‐NpC/γ‐CD@SR101 is ≈8.5 times enhanced, with the corresponding ΦPL rising from 0.87% to 19.13%. Besides, this strategy is also successfully applied into ionic bond system (SA/R), and the ΦPL for SA/BDA/γ‐CD@RhB can reach 24.05%. Furthermore, these materials with good RTP performance are applied in multiple information encryption, optical information storage, and anti‐counterfeiting. [ABSTRACT FROM AUTHOR]

In this work, large-eddy simulations of hydrogen dispersion from turbulent subsonic hydrogen-gas emissions in a 5.8 × 0.9 × 0.8 m 3 open-ended channel are described. Such numerical modeling of hydrogen-related processes can provide new insights into the safety aspects of hydrogen, an increasingly more common energy carrier, particularly related to explosion hazards. Ten simulations, with jet mass flow rates ranging from 0.08 g/s to 1.27 g/s, have been simulated using the open-source OpenFOAM® 10 suite. The predicted concentrations in the channel are compared to corresponding experimental data, generally showing good agreement. Two distinct dispersion regimes are observed from the numerical data; a strongly stratified "filling box" regime is found for hydrogen mass flows ≲ 0. 15 g/s, whereas a more homogenized "fading box" regime emerges for higher mass flows. Based on the local Froude number in the channel, a novel model for the momentum length scale of the hydrogen jet is proposed, applicable to downward, strongly buoyant (i.e., non-Boussinesq) jets. It is demonstrated that the ratio of this length scale to the vertical length scale of the geometry can be used to predict the dispersion regime, which may benefit simplified predictive models for hydrogen concentrations and, consequently, ignition risks. • Experimental and numerical study of hydrogen dispersion in an open-ended channel. • Subsonic, turbulent jets with mass flows from 0.09 to 1.27 g/s. • Predicted concentrations compared to experimental measurements at 29 locations. • Two dispersion regimes, "filling box" and "fading up box", identified. • A new jet momentum-length model for strongly buoyant, downward jets is proposed. [ABSTRACT FROM AUTHOR]

In this study, nano‐magnesium oxide (MgO) was modified with surfactants sodium polyacrylate, polyvinyl alcohol (PVA) and polyethylene glycol (PEG) based on the agglomeration problem of nano‐MgO in cement. The surfactant PEG with the best modification effect was selected to modify nano‐MgO and synergize with the dispersing effect and early‐strengthening effect of triethanolamine (TEA) to prepare a new type of composite cementitious sealing material with high early compressive strength and good fluidity. The optimal ratio of the mass fraction of the composite early‐strengthening agent was determined by the response surface method: 0.02% PEG + 2% nano‐MgO + 0.04% TEA. The effects of the composite early‐strengthening agent on the cementitious sealing material were investigated by the compressive strength, fluidity, setting time, X‐ray diffraction experiments (XRD), thermogravimetric (TG‐DSC), scanning electron microscopy (SEM), etc. The effect of the composite early‐strengthening agent on the cementitious sealing material was also investigated by the response surface method. The compressive strength of the composite cement specimens at 1d, 3d, and 7d was increased by 92.59%, 35.50%, and 47.73% respectively compared to the blank group. In comparison to the control group, the flowability increased by 31.96%, and the initial and final setting time was shortened to 377 min and 394 min, respectively. [ABSTRACT FROM AUTHOR]

The article "Diffusion-driven flows in a nonlinear stratified fluid layer" delves into diffusion-driven flow in a nonlinearly density-stratified fluid between tilted parallel walls. It introduces an asymptotic expansion technique to accurately approximate velocity, density, and pressure fields, replacing the constant diffusion coefficient with a derivative-dependent function. Numerical simulations confirm the accuracy of the approximations, emphasizing the significance of nonlinearly stratified fluids and diffusion-driven flow in natural settings. The document further explores diffusion-driven flows in tilted parallel-plate channels with nonlinear density stratification, highlighting the impact of diffusion-driven flow on dispersion and comparing different modeling approaches. Additionally, it contains a collection of research articles on fluid dynamics, natural convection, dispersion, and diffusion in various environments, offering valuable insights into fluid behavior in complex systems. [Extracted from the article]

The diffraction efficiency of blaze gratings is optimized only at a specific frequency due to a fixed blaze angle, resulting in reduced and variable diffraction efficiencies over the working frequency band. Additionally, blazed gratings demonstrate polarization dependence due to their groove structures and the interaction of light with their surfaces. Consequently, designing gratings with constant diffraction efficiencies across a wide frequency bandwidth while maintaining polarization independence remains a challenge. Here, a design paradigm of dispersion engineerable meta‐grating inspired by orthogonal harmonic oscillations (OHO) is presented. Utilizing the OHO model, the phase dispersion of a metasurface can be precisely controlled, which applies to any unit cell featuring two orthogonal electromagnetic resonances. As a proof of concept, a polarization‐insensitive meta‐grating is showcased, where the blazed angle adapts with the incident frequency, ensuring broadband performance. In the experiment, the adaptively‐blazed grating measured an optimized and constant diffraction efficiency of ≈80% over the working wavelength range, i.e., 8.7–12.2 µm. The difference in diffraction efficiency between the two perpendicular linear polarization states remains within 4.6%. The proposed paradigm paves the way for meta‐device design based on precise dispersion engineering, which has potential applications in spectrometers, broadband beam forming and steering, hyperspectral imaging, etc. [ABSTRACT FROM AUTHOR]

The twin zero group velocity (ZGV) points are observed, which belong to the fundamental symmetric branch (S0) of Lamb waves propagating in a composite traction-free layered plate containing odd number of layers with alternating physical properties. It is shown that in a vicinity of these ZGV points an ambiguity of dispersion spectrum takes place, resulting in the appearance of several waves, which (i) belong to the same fundamental mode; (ii) satisfy the same boundary conditions; and, (iii) propagate at the same frequency, however (iv) with different phase velocities. The analysis is based on a combination of Cauchy formalism and the exponential fundamental matrix method. [ABSTRACT FROM AUTHOR]

Fiber optic research continues to develop due to the need for fast information technology. The input signal in an optical fiber is in the form of a soliton wave that propagates in the fiber with a balanced index of refraction, dispersion, and diffraction. Fiber optics may lose some of the signal over time if they solely use a nonlinear refractive index. This study aims to examine into the dynamics and decoherence of multi-peak solitons caused by electromagnetic signal attenuation and potential trap in the propagation via optical fibers. The methods used start with the stationary solution of the nonlinear Schrödinger Cubic Quintic equation, the Newton-Raphson method, and the fourth-order Runge-Kutta. In stationary solutions, the p (state energy) and ρ (Lèvy index) values affect the number, pulse width, and height of soliton peaks. Increased p and ρ values lead to increased instability, causing the data transmitted into the optical fiber to collapse and become unreadable by the receiver. In the excited state (p > 0), the decoherence phenomenon occurs and causes wave instability and destruction. In term of energy intensity, a stable form of transmission in the ground state has a pattern of continuously weakening, decreasing, and smoothing, while in the excited state there is a spike in the intensity of the electromagnetic wave. Based on this study, multi-peak solitons can only be applied for propagation distances, which tend to be short due to their dynamics and decoherence. [ABSTRACT FROM AUTHOR]

Multistatic imaging systems are commonly used in radar systems and microwave imaging. In these systems, many antennas are arranged three-dimensionally and connected to RF switches. The length of each transmitter (Tx) and receiver (Rx) channel differs slightly, causing artifacts in high-resolution image reconstruction. This study presents a novel method for the phase calibration of multistatic systems. This method does not require system reconstruction and can automatically perform phase calibration in a short time. This method is expected to facilitate an accurate phase measurement in multistatic systems. The approach involves phase calibration by analyzing the reflection coefficients of antenna elements in the time domain. Imaging experiments were performed on a multistatic imaging system using this calibration method, and the position and shape of a metal rod with a diameter one-fourth of a wavelength were reconstructed by simple back-projection with an accuracy beyond the diffraction limit. [ABSTRACT FROM AUTHOR]

The dispersion of nano‐SiO2 (NS) in cement plays a critical role in enhancing the properties of cementitious materials. In this study, the combination of ultrasonic dispersion and polycarboxylic acid water reducing agent (PCE) was used to significantly improve the dispersion of NS. The effects of ultrasonic dispersion time, NS content, and PCE content on dispersion quality were investigated, alongside their impact on mechanical properties, electrical resistivity, and frost resistance. The results demonstrated that this synergistic method optimized the dispersion of NS, leading to superior mechanical properties and frost resistance. With an ultrasonic dispersion time of 40 min, NS content of 1.0 wt.%, and PCE content of 0.75 wt.%, the cement paste achieved its optimal performance. Compared to non‐dispersed samples, compressive strength increased by 33.7%. After 75 freeze–thaw cycles, the mass loss was 2%, the relative dynamic elastic modulus was 99.15%, and the strength loss was 13.74%. [ABSTRACT FROM AUTHOR]

Diffusion-driven flow is a boundary layer flow arising from the interplay of gravity and diffusion in density-stratified fluids when a gravitational field is non-parallel to an impermeable solid boundary. This study investigates diffusion-driven flow within a nonlinearly density-stratified fluid confined between two tilted parallel walls. We introduce an asymptotic expansion inspired by the centre manifold theory, where quantities are expanded in terms of derivatives of the cross-sectional averaged stratified scalar (such as salinity or temperature). This technique provides accurate approximations for velocity, density and pressure fields. Furthermore, we derive an evolution equation describing the cross-sectional averaged stratified scalar. This equation takes the form of the traditional diffusion equation but replaces the constant diffusion coefficient with a positive-definite function dependent on the solution's derivative. Numerical simulations validate the accuracy of our approximations. Our investigation of the effective equation reveals that the density profile depends on a non-dimensional parameter denoted as $\gamma$ representing the flow strength. In the large $\gamma$ limit, the system is approximated by a diffusion process with an augmented diffusion coefficient of $1+\cot ^{2}\theta$ , where $\theta$ signifies the inclination angle of the channel domain. This parameter regime is where diffusion-driven flow exhibits its strongest mixing ability. Conversely, in the small $\gamma$ regime, the density field behaves like pure diffusion with distorted isopycnals. Lastly, we show that the classical thin film equation aligns with the results obtained using the proposed expansion in the small $\gamma$ regime but fails to accurately describe the dynamics of the density field for large $\gamma$. [ABSTRACT FROM AUTHOR]

We report on Lagrangian statistics of turbulent Rayleigh–Bénard convection under very different conditions. For this, we conducted particle tracking experiments in a $H=1.1$ -m-high cylinder of aspect ratio $\varGamma =1$ filled with air (Pr = 0.7), as well as in two rectangular cells of heights $H=0.02$ m ($\varGamma =16$) and $H=0.04$ m ($\varGamma =8$) filled with water (Pr = 7.0), covering Rayleigh numbers in the range $10^6\le {\textit {Ra}}\le 1.6\times 10^9$. Using the Shake-The-Box algorithm, we have tracked up to 500 000 neutrally buoyant particles over several hundred free-fall times for each set of control parameters. We find the Reynolds number to scale at small Ra (large Pr) as $ {\textit{Re}} \propto {\textit{Ra}}^{0.6}$. Further, the averaged horizontal particle displacement is found to be universal and exhibits a ballistic regime at small times and a diffusive regime at larger times, for sufficiently large $\varGamma$. The diffusive regime occurs for time lags larger than $\tau _{co}$ , which is the time scale related to the decay of the velocity autocorrelation. Compensated as $\tau _{co} {\textit {Pr}}^{-0.3}$ , this time scale is universal and rather independent of $ {\textit {Ra}}$ and $\varGamma$. We have also investigated the Lagrangian velocity structure function $S^2_i(\tau)$ , which is dominated by viscous effects for times smaller than the Kolmogorov time $\tau _\eta$ and hence $S^2_i\propto \tau ^2$. For larger times we find a novel scaling for the different components with exponents smaller than what is expected in the inertial range of homogeneous isotropic turbulence without buoyancy. Studying particle-pair dispersion, we find a Batchelor scaling (${\propto }\,t^2$) on small time scales, diffusive scaling (${\propto }\,t$) on large time scales and Richardson-like scaling (${\propto }\,t^3$) for intermediate time scales. [ABSTRACT FROM AUTHOR]

The article delves into the phenomenon of droplet clustering in evaporating sprays, focusing on the collective vaporization of droplets in turbulent airflow. Through experimental investigation, the study identifies the Group number as a key indicator of vaporization mode, revealing a wide range of Group numbers and highlighting the multiscale clustering of evaporating droplets. By utilizing Voronoi analysis, the research sheds light on the importance of quantifying droplet grouping effects for understanding system performance and predicting spray evaporation rates. Additionally, the document includes a comprehensive list of references to related studies on fluid dynamics, particle-laden turbulence, and particle behavior in turbulent flows, offering valuable insights into complex fluid dynamics and particle interactions. [Extracted from the article]

Present‐day air quality is known through dense monitoring and extensive pollution control mechanisms. In contrast, knowledge of historical pollution, particularly before the industrial revolution, is accessible only through occasional reports of singular local events and through natural archives such as ice or sediment cores that record global‐scale pollution. However, the regular local to regional pollution that most affects human life is hardly known. Historical sciences have argued both for and against significant air pollution in and around historic cities and manufacturing sites. For the Roman era, it has been hypothesized that air quality played a role in several patterns of action of the period. However, to the author's knowledge, there are no quantitative studies of Roman emissions. Using the results of modern experimental archaeology, this study attempts to quantify the emissions from Roman pottery kilns and their impact on surrounding human settlements. It is shown that although the pollution did not reach today's limits, it must have approached levels known to cause adverse health effects. A series of additional test simulations have been conducted to determine how these first results might be improved in the future. [ABSTRACT FROM AUTHOR]

This paper investigates a quantitative comparison of the Love wave propagation due to traction-free and rigid boundary surfaces on the piezoelectric-dispersive layer over a non-dispersive initially stressed half-space. The model is considered (a) transversely isotropic piezoelectric material in the upper layer, (b) exponentially increasing dispersive (non-homogeneous) layer in the intermediate, and (c) initially stressed non-dispersive (homogeneous) medium in the lower half-space. Electrical potential fields in the piezoelectric layer are defined in terms of electrical potential function with open and short circuit piezoelectricity using the quasi-static Maxwell's equation. We have derived analytical dispersion relations for two cases of boundary conditions: (i) free surface with zero tractions and (ii) rigid boundary, in both the open and short circuit cases. The validities of the dispersion relations are shown by deriving some particular cases and compared with the classical dispersion relation of the Love wave. A novel numerical representation of changes in displacement amplitude with depth and comparative effect of various piezoelectric materials such as PZT-4, PZT-5A, PZT-7A, and BaTiO3 are shown using MATLAB software. The rigid boundary surface case is more effective than traction-free boundary surfaces in terms of electromechanical coupling factor. It is also identified that there are significant effects on the dispersion of the Love-type waves due to different boundary conditions on the upper surface of the model. These comparative studies highlight the present work and may be helpful in the fields of solid mechanics and material fabrication processes. [ABSTRACT FROM AUTHOR]

Oil spills pose significant threats to marine and freshwater environments, impacting ecosystems and drinking water sources. The present review incorporated an up‐to‐date statistical analysis of the oil spills globally including the types and sources of oil spills and the main habitats affected by the past incidents. It presented immediate and long‐term effects on aquatic organisms and habitats highlighting the necessity for action to protect the aquatic environment. The paper also elucidated a range of effective remediation and cleanup methods, presenting a comprehensive toolkit to mitigate ecological damage. Noticeably, the review identified crucial knowledge gaps in the literature: (i) the absence of marine plastic pollution in studies on oil spill impacts and (ii) the absence of a modeling framework that considers the presence of microplastics in the spillage region and their impacts on the overall weathering rate. From synthesizing essential knowledge on oil spill dynamics and identifying the knowledge gap in the literature, this review aims to enhance understanding and guide future research. [ABSTRACT FROM AUTHOR]

Fullerene has been acknowledged as a significant nanocarbon nanofiller enhancing the imperative polymer characteristics. Since, thermoplastic polymers constitute a large group of polymeric materials, fullerene has been used as reinforcement in these matrices mostly via non-covalent means. This state-of-the-art review article summarizes thermoplastic polymer nanocomposites reinforced with fullerene nano-additives without involving any covalent interactions. Accordingly, thermoplastic polymer/fullerene nanocomposites of interest have non-covalent or physical interactions in the matrix-nanofiller such as van der Waals forces, electrostatic interactions, hydrogen bonding, and aromatic stacking interactions. Number of thermoplastic polymers including polyamide, polyurethanes, and block copolymers have been non-covalently or physically reinforced with the fullerene molecules. Ensuing high performance thermoplastic polymer/fullerene nanocomposites exhibited improved microstructure, electrical, mechanical, thermal, and other physical properties. Enhancements in the thermal, mechanical, and electrical properties of the thermoplastic/fullerene nanomaterials were found dependent upon the nanofiller contents, orientations, interfacial effects, and processing. Consequently, the polyamide/fullerene systems were found efficient to enhance the glass transition up to 260°C, in addition to optimum mechanical properties. Polyurethane/fullerene systems performed better for improved tensile strength and young's modulus features up to 90 MPa and 48 GPa, respectively. System based on poly (methyl methacrylate) and fullerene has resulted in high thermal degradation temperature in the range of 501-633°C with fine electrical conductivity of 1.3 Scm−1. Using combination of fullerene and graphene nanofiller (due to synergistic effects) has been found to improve the electrical conductivity considerably in the range of 1.8–2.5 Scm−1 for a polystyrene and block copolymer system. However, attaining fine fullerene nanoparticle dispersion of non-covalently reinforced matrices have been found important affecting the final nanocomposite properties. Consequently, processability and essential characteristics of non-covalently fullerene filled nanocomposites can be influenced due to nanoparticle aggregation. Hence, the physical property enhancement potential of physical linking between the non-covalently linked thermoplastics-fullerene has been portrayed in this article. Research on non-covalently interacted thermoplastic polymer/fullerene nanocomposites revealed technical potential ranging from energy/electronic devices to engineering and biomedical sectors. This review article can be a useful guide for the field researchers towards the development of advanced systems using non-covalently linked polymer/fullerene nanomaterials for future technical applications. [ABSTRACT FROM AUTHOR]

Basalt fibers were widely used as reinforcing matrix materials because of their thermal and chemical stability and environmental friendliness. The properties of composite materials were affected by the interaction between the basalt fibers and matrix materials. Surface modification of basalt fibers and the dispersion property have become key points of research in recent years. This study focuses on the impact of a dispersant on surface modification. Basalt fibers were dispersed by polyethylene glycol (PEG) before modification with 3-aminopropyltriethoxysilane (KH550), which significantly increased the surface roughness, thus increasing the surface area and facilitating mechanical bonding. The morphology, structure, and composition were characterized via scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and X-ray photoelectron spectroscopy analysis (XPS), respectively. The distribution characteristics of fiber were evaluated by the response surface method. When the mass fraction of PEG was 0.5 wt.%, the modification time was 2.5 hours, and the modification temperature was 60°C, the fiber dispersion degree in KH550 solution reached 83%. The grafting degree test indicates that the weight of the grafting increased to 6.67 times that of the undispersed basalt fibers. This enhancement allowed for greater grafting of the KH550, thereby optimizing the effect of modified fibers. [ABSTRACT FROM AUTHOR]

Research into particulate polymer composites is of significant interest due to their potential for enhancing material properties, such as strength, thermal stability, and conductivity while maintaining low weight and cost. Among the various techniques for preparing particle-based composites, ultrasonic wave stimulation is one of the principal laboratory-scale methods for enhancing the dispersion of the discontinuous phase. Nevertheless, there is a scarcity of empirical evidence to substantiate the impact of stimulating materials with natural sound frequencies within the acoustic spectrum, ranging from 20 Hz to 20 kHz, during their formation process. The present work investigates the effect of acoustic stimuli with frequencies of 56, 111, and 180 Hz on the properties of an acrylic-based polymer and its discontinuous carbon-based composites. The results indicated that the stimulus frequency affects the cure time of the studied systems, with a notable reduction of 31% and 21% in the cure times of the neat polymer and carbon-nanofiber-based composites, respectively, after applying a frequency of 180 Hz. Additionally, the higher stimulation frequencies reduced porosity in the samples, increased the degree of dispersion of the discontinuous phase, and altered the composite materials' thermal, optical, and electrical behavior. [ABSTRACT FROM AUTHOR]

A new study of the effect of a previously unstudied factor on dispersion, and repeatability of the injected sample. The design idea is based on manufacturing two new microcells with different volumes used in flow injection (FI) analysis systems and determining the measurements of the external structure, internal paths, and the measuring chamber with high accuracy. The efficiency of the FI system was tested by measuring the dead volume, and it was found to be zero. All measurements (n=5) were implemented by using the concentration 10.00 mg/L of Toluidine Blue dye solution at the wavelength 625.0 nm, flow cells with the volumes (35.0, 80.0, and 450.0) μL, sample volumes (39.25 and 78.50) μL, and flow rates (2.6, 4.5, and 6.6) mL/min. The results of the study indicate a relationship between flow cell volume and dispersion values. This relationship becomes apparent when other factors, such as sample volume and flow rate, are changed. [ABSTRACT FROM AUTHOR]

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In the middle and late stages of offshore carbon-rich gas reservoir development, insufficient reservoir energy poses significant challenges and difficulty in improving gas recovery. Injecting CO2 back into the reservoir is a promising development approach that can address both carbon emissions and enhanced gas recovery (EGR). During the CO2 injection process, the CO2–CH4 dispersion significantly impacts the recovery of CH4. To understand the mass transfer and dispersion laws of CO2 and high-carbon natural gas under current in situ reservoir conditions, this study conducted 1-m-long core experiments to investigate the effects of different gas compositions and permeabilities on gas recovery and diffusion laws in offshore reservoirs, taking into account the evolution of permeability in the porous medium. The experimental results indicate that the higher carbon concentration helps reduce mixing with formation gas, which consists of 70% methane, 25% nitrogen, and 5% carbon dioxide, resulting in a smaller diffusion coefficient. Under the conditions of an injection rate of 0.4 mL/min, a temperature of 81 °C, and a pressure of 7 MPa, the diffusion coefficient decreases by 27.5% as the carbon dioxide concentration increases from 70% to 90%, resulting in a 1.5% increase in recovery efficiency. As the permeability decreases, the viscous resistance of the fluid increases, leading to longer breakthrough times, and the reservoir fluid becomes more akin to piston displacement, reducing the degree of dispersion. The findings of this study provide guidance for optimizing gas injection strategies by reducing CO2 dispersion and further enhancing natural gas recovery. [ABSTRACT FROM AUTHOR]

Understanding the dispersion of floating objects and ocean properties at the ocean surface is crucial for various applications, including oil spill management, debris tracking and search and rescue operations. While mesoscale turbulence has been recognized as a primary driver of dispersion, the role of submesoscale processes is poorly understood. This study investigates the largely unexplored mechanism of dispersion by refracted wave fields. In situ observations demonstrate significantly faster and distinct dispersion patterns for objects influenced by wind, waves and currents compared to those solely driven by ocean currents. Numerical simulations of wave fields refracted by ocean eddies corroborate these findings, revealing diffusivities that exceed those of turbulent diffusion at scales up to 10 km during energetic sea states. Our results highlight the importance of ocean waves in dispersing surface material, suggesting that refracted wave fields may play a significant role in submesoscale spreading. As atmospheric forcing at the ocean surface will only strengthen due to anthropogenic contributions, additional research into wave refraction is necessary. This requires concurrent high-resolution measurements of wind, waves and currents to inform the revisions of large-scale coupled models to better include the submesoscale physics. [ABSTRACT FROM AUTHOR]

This review paper summarizes properties, uses, working principle and applications of the Photonic Crystal Fiber and its comparison with conventional fiber. In simple terms, conventional optical fiber is a wired transmission medium that offers an optical channel that is more reliable as well as flexible than the atmosphere. The most crucial aspects of any communication systems are its bandwidth and signal-to-noise ratio, which determine the channel's capacity. At 1550 nm, the optical fiber link currently has a loss of 0.2 dB/km. A single fiber-optic communication link has a bandwidth of about 50 THz. Thus, the foundation of modern communication systems is made up of fiber optic communication systems. Optical fiber is used in a wide range of sensor applications in addition to communication. However, optical fiber is not able to offer design flexibility. Thus, Photonic Crystal Fiber--a desirable substitute fiber--came into existence. With only little changes to its geometrical dimensions, photonic crystal fiber offers exceptional design freedom and opens opportunities in various sensing applications. This article covers comparative analysis of different sensing parameters like birefringence, confinement loss for liquids mediums like water, ethanol, benzyne, glucose solution, human mucosa etc. The geometrical structural dependence of sensitivity of PCF based sensors have been reviewed. Further, for different gases their absorption wavelengths, relative sensitivity, confinement loss at different operating frequencies sensitivity and effective mode area have been reviewed. Performance parameters of PCF-based temperature sensors for different PCF designs have also been analysed. It is suggested that by adjusting the geometrical structure of air holes the performance of PCF based sensors can be optimized. [ABSTRACT FROM AUTHOR]

This work examines how the real part (dispersion) and imaginary part (absorption or gain) of susceptibility control the entropy in the ladder-plus-Y double quantum dot structure under spontaneously generated coherence (SGC). The results show that the higher real part of susceptibility is related to the higher SGC factor and the structure transfer between the normal and anomalous dispersion but, in a way, depends on the strength of the probe field. At a very weak probe, the system transfers from the gain case under no SGC to an absorption case with increasing SGC and returns to gain under a complete SGC. High entropy is associated with high SGC. When the probe field grows, the system pinned the gain case, but the gain and dispersion are reduced depending on probe increment, reducing the entropy. In a few words, high entropy is associated with high dispersion and gain resulting from a weak probe. [ABSTRACT FROM AUTHOR]

The article "Rotational Taylor dispersion in linear flows" in the Journal of Fluid Mechanics presents a rotational Taylor dispersion theory for spheroidal particles in linear flows, examining the impact of flow-induced rotations and Brownian diffusion. The study reveals enhanced rotational dispersion in simple shear and reduced dispersion in extensional flow, offering analytical expressions for transport coefficients and validating results through numerical simulations. The research compares classical Taylor dispersion in position space with rotational dispersion in orientation space, emphasizing the influence of advection and diffusion coupling on transport dynamics. The document also includes a collection of research articles on fluid mechanics topics like Brownian motion, Taylor dispersion, and active suspensions, providing valuable insights into the dynamics of fluid systems. [Extracted from the article]

We investigated the Diels‐Alder reaction of 6,13‐bis(triisopropylsilylethynyl)pentacene (1) with small dienophiles such as (bridged) dihydronaphthalenes/cyclohexenes that yielded adducts at the central ring, the other dienophiles predominantly or exclusively attacked the unsubstituted off‐center ring. The difference in regioselectivity was investigated by DFT calculations. Apart from dispersion interactions, it is due to the steric demand of the dienophiles, which need to fit in between the silylethynyl substituents to react at the central ring. Epoxynaphthalene adducts of 1 as well as its anthracene and tetracene congeners were deoxygenated, easily furnishing triarenobarrelenes with TIPS‐ethynyl substituents at the bridgeheads, attractive building blocks for porous solids and higher acene‐based trimers. [ABSTRACT FROM AUTHOR]

AbstractThe experimental study assessed the impact of choline chloride cation-based ionic liquid (IL), on the dispersion stability and wear characteristics of copper (II) oxide (CuO) nanoparticles (NPs) in synthetic base oil (PAO 10). CuO NPs, averaging 50 nm in size, underwent surface modification using varying concentrations of the IL (0.25%, 0.5%, 0.75%, and 1% by weight). The formulations were subjected to sliding wear tests to evaluate their wear behavior. Analysis of the worn surfaces utilized scanning electron microscopy, energy-dispersive x-ray spectroscopy, and atomic force microscopy. The results indicated that the combination of 0.75% IL and 1% CuO NPs provided optimal dispersion and exhibited effective surface mending, enhancing wear protection by 21.1% than that of PAO 10. The formulation containing 1% IL and 1% CuO NPs demonstrated the highest load carrying capacity among all tested compositions. In terms of wear behavior, the nanolubricant formulations with 0.75% and 1% IL outperformed the lubricant formulation containing 1 wt% of the commercial antiwear additive Zinc dialkyldithiophosphates (ZDDP). [ABSTRACT FROM AUTHOR]

Mechanistic investigations at the density functional theory level of organic and organometallic reactions in solution are now broadly accessible and routinely implemented to complement experimental investigations. The selection of an appropriate functional among the plethora of developed ones is the first challenge on the way to reliable energy barrier calculations. To provide guidelines for the choice of an initial and reliable computational level, the performances of commonly used non‐empirical (PBE, PBE0, PBE0‐DH) and empirical density functionals (BLYP, B3LYP, B2PLYP) were evaluated relative to experimental activation enthalpies. Most reactivity databases to assess density functional performances are primarily based on high level calculations, here a set of experimental activation enthalpies of organic and organometallic reactions performed in solution were selected from the literature. As a general trend, the non‐empirical functionals outperform the empirical ones. The most accurate energy barriers are obtained with hybrid PBE0 and double‐hybrid PBE0‐DH density functionals, both providing similar performance. Regardless of the functional under consideration, the addition of the GD3‐BJ empirical dispersion correction does not enhance the accuracy of computed energy barriers. [ABSTRACT FROM AUTHOR]

AbstractAn investigation on the propagation of bending waves along the edge of a piezoelectric thin plate resting on an elastic foundation (cf. Pasternak foundation) and under the action of a point-load is carried out in this paper. The displacement field of the plate is based on the classical plate theory. The Kelvin-Voigt type viscoelastic model is used to examine the viscous effect on the characteristics of the bending wave. The Moore-Gibson-Thompson (MGT) thermoelastic equation is solved for an external time variant harmonic heat source at the upper surface of the plate. The piezoelectric potential is obtained for an electrode-covered upper surface and an electrically shorted lower surface. The displacements of the propagating bending wave along the edge are examined under a time-harmonic point-load acting near the vicinity of the free edge of the plate. The well-known Green function technique and Fourier transform method are implemented to generate an analytical solution for the non-homogeneous boundary value problem. The examination of the derived explicit form of the dispersion relationship and the displacements of the bending edge wave under external loading are discussed and presented both analytically and graphically, and the results are summarized. [ABSTRACT FROM AUTHOR]

The quantity of silane chemically bonded to the organoclay's surface significantly influences its dispersion within the polymer matrix, as well as the interfacial interaction. This research presents a groundbreaking method for enhancing the surface properties of montmorillonite (Mt) through the use of γ‐(methacryloxy) propyl trimethoxy silane (KH570) coupled with acid treatment, leading to increased grafting efficiency. Confirmed by FT‐IR, TGA, and XRD, the process effectively bonds organo‐silanes to Mt and achieves a high grafting level of 1.59 mequiv/g. Utilizing a latex compounding method, Mt/rubber nanocomposites are synthesized with thoroughly modified clay for peak performance. Dispersion and interfacial properties are evaluated through XRD, TEM, AFM, and DMTA. The findings reveal that the well‐modified Mt is an exceptional filler, ensuring a high level of dispersion and robust interaction with the rubber matrix. This synergy translates to a marked improvement in the mechanical properties of the composite, with notable enhancements observed in both tensile strength and elongation at break of 9.7 MPa and 1141%, respectively. This innovative approach to the graft modification of clays presents a potent method, offering the potential for the industrial‐scale manufacture of high‐performance clay‐based composites. Highlights: A processing method for preparing high grafting clay with a silane coupling agent.Functionalized clay presents better nano‐dispersion in the polymeric matrix.Strong covalent interfacial interaction is constructed between clay and rubber.Tensile Strength and elongation at break of the composites are obliviously improved. [ABSTRACT FROM AUTHOR]

Fiber optics telecommunication is the currently established backbone infrastructure for most of the information flow across the world. New services and applications are causing an exponential increase in Internet traffic, increasing transmission rate, and high bandwidth-demanding applications have been propelling the data rate per wavelength to approach the speed limit of electronics. In a few years, the current fiber optic communication system infrastructure will not be able to meet this demand because fiber nonlinearity dramatically limits the information transmission rate. Also, the dispersion phenomenon is a problem for high bit rates and long-haul optical communication systems. An easy solution to this problem is optical solitons pulses that preserve their shape over long distances. An optical soliton is formed by balancing nonlinearity (self-phase modulation) and dispersion phenomenon (group velocity dispersion). In this review article, a detailed study of optical solitons is presented along with its recent progress. Advanced numerical methods such as Darboux transform (DT), digital back propagation, split step Fourier, and forward–backward methods are also discussed in this paper which is used for solving higher-order solitons. [ABSTRACT FROM AUTHOR]

Elastic Optical Network (EON) is gaining a lot of attention these days because of its capability to dynamically utilize the network resources. It is possible to alter data rates in accordance with the required application by adjusting a number of spectrum slots which enhances spectral efficiency. However, it is difficult for new requests to access the usage of spectrum resources during the entire process especially when the spectrum is split into a number of small segments. Another key challenge in EON is to achieve effective routing and spectrum allocation. This entails looking for a specified route and identifying contiguous aligned spectrum slots for allocation to various requests. In this way, EON aims maximizing the connection while using the least amount of available spectrum resources. With this in mind, this research developed a first random fit (FRF) spectrum allocation technique that takes into account dispersion, which is a major physical flaw in optical networks. This scheme includes the effect of dispersion for the spectrum allocation approach. Using a FRF approach, this scheme tends to allocate a greater number of connection requests and spectrum is utilized in more efficient way. Starting with the lowest indexed slot, this scheme uses the First Fit algorithm and the less stable modulation technique like BPSK to search for and assign the spectrum slot. A random fit assignment strategy is used with a more robust modulation technique (QPSK) to exploit the next higher indexed spectrum slot which suffers larger dispersion effect. Longer light path requests are assigned to lower indexed spectrum slot (lower dispersion slots) using BPSK modulation technique, while shorter light path requests are sent to next higher indexed spectrum slot (greater dispersion slots) using QPSK modulation technique capturing the dispersion sensitive technique. The results show that the proposed technique achieves a minimal bandwidth blocking probability (BBP) of 0.048, Eye opening Penalty (EOP) of 45.45 dB and Quality Factor of 3.889 and B.P compared with other First Fit (FF) and Random Fit (RF) spectrum allocation schemes. [ABSTRACT FROM AUTHOR]

In order to understand the dispersion of hydrogen (H2) leaked in packed beds of nonporous/porous particles in a partially open space practically, the dispersion of H2 in the particle layers of glass beads and soil was analytically studied using a computational fluid dynamics code to be compared with the experiments and to elucidate the effects of the particle layer. The packed beds in the partially open space can be considered as a basic model for all processes of transfer, treatment, storage, and disposal of radioactive materials containing fuel debris in the decommissioning of nuclear facilities after a severe accident. The H2 flowing out from a single leak point in the particle layer of nonporous glass beads was affected by buoyancy around the leak point and diffused directly above the leak point in an elliptical shape faster than in the horizontal direction. After that, when it reached the air layer in the head space above the particle layer, the H2 spread horizontally, formed a large concentration gradient near the boundary between the particle layer and the air layer, and further diffused in the air layer until the H2 concentration became about 1/3 or less of the concentration near the surface of the particle layer. When the particle diameters were 512 μm and 1200 μm, this tendency was more pronounced when the porosity was the same and the particle diameter was smaller. The calculations largely reproduced the experimental concentration distributions. When the particle layer was porous decomposed granite soil, the diffusion behavior of H2 in the particle layer proceeded in the same manner as in the case of the glass beads. However, a large concentration gradient was formed near the boundary between the particle layer and the air layer, and then H2 diffused in the air layer until the H2 concentration became below the lower combustion limit. It was suggested through sensitivity analysis that the air permeability coefficient had a large effect on the time course of the H2 concentration distribution. Based on this information, we further simulated H2 behavior in the vessel containing the H2 leaked particle layer. By inserting multiple vent pipes without considering H2 generation distribution and particle properties in the particle layer, H2 accumulated from one pipe was discharged by buoyancy without depending on the H2 generation distribution and particle properties in the particle layer and air flowed in from the other pipe. It was suggested that such a natural ventilation process would reduce the H2 concentration in the container. [ABSTRACT FROM AUTHOR]

In this work, we propose a novel dual guided PCF design capable of supporting the transmission of 68 OAM modes. The innovative design features a specialized structure with multiple layers composed of pure silica and SF57 material arranged alternately. To enhance physical strength and minimize loss, the fiber is enclosed by a perfectly matched layer (PML). Air holes are strategically added and optimized in the third and fifth layers. Through numerical analysis, we observed that the proposed design yields excellent results across all evaluated parameters. The maximum confinement loss recorded is 10–12 dB/m. The effective refractive index values range from 1.444 to 1.8, with effective refractive index difference values in the order of 10–2. Furthermore, the modal purity and power fraction values exceed 99% for all modes. Dispersion values are maintained below 9.87 ps/THz/cm, and crosstalk values are less than − 12 dB. These results demonstrate the potential of our dual guided PCF design in meeting the increasing demands for high-speed and reliable communicating systems. [ABSTRACT FROM AUTHOR]